Integrated circuits use output buffers to transform relatively weak internal signals into stronger signals suitable for external use, such as for transmission to other integrated circuits on printed circuit boards. However the layout and termination of signal lines on printed circuit boards vary widely from application to application. For example integrated circuits on printed circuit boards with short, lightly loaded signal lines do not need output buffers as strong as printed circuit boards with longer, heavily loaded signal lines. If the output buffers are too strong, they may overdrive lightly loaded output signal lines and cause signal failure due to underdamping or ringing on the signal lines. If the output buffers are too weak, they may not be able to drive heavily loaded output signal lines in sufficient time and also cause signal failure.